mifillarc.c

/************************************************************

Copyright 1989, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.

Author:  Bob Scheifler, MIT X Consortium

********************************************************/


#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif

#include <math.h>
#include <X11/X.h>
#include <X11/Xprotostr.h>
#include "regionstr.h"
#include "gcstruct.h"
#include "pixmapstr.h"
#include "mifpoly.h"
#include "mi.h"
#include "mifillarc.h"

#define QUADRANT (90 * 64)
#define HALFCIRCLE (180 * 64)
#define QUADRANT3 (270 * 64)

#ifndef M_PI
#define M_PI	3.14159265358979323846
#endif

#define Dsin(d)	sin((double)d*(M_PI/11520.0))
#define Dcos(d)	cos((double)d*(M_PI/11520.0))

void
miFillArcSetup(xArc *arc, miFillArcRec *info)
{
    info->y = arc->height >> 1;
    info->dy = arc->height & 1;
    info->yorg = arc->y + info->y;
    info->dx = arc->width & 1;
    info->xorg = arc->x + (arc->width >> 1) + info->dx;
    info->dx = 1 - info->dx;
    if (arc->width == arc->height)
    {
	/* (2x - 2xorg)^2 = d^2 - (2y - 2yorg)^2 */
	/* even: xorg = yorg = 0   odd:  xorg = .5, yorg = -.5 */
	info->ym = 8;
	info->xm = 8;
	info->yk = info->y << 3;
	if (!info->dx)
	{
	    info->xk = 0;
	    info->e = -1;
	}
	else
	{
	    info->y++;
	    info->yk += 4;
	    info->xk = -4;
	    info->e = - (info->y << 3);
	}
    }
    else
    {
	/* h^2 * (2x - 2xorg)^2 = w^2 * h^2 - w^2 * (2y - 2yorg)^2 */
	/* even: xorg = yorg = 0   odd:  xorg = .5, yorg = -.5 */
	info->ym = (arc->width * arc->width) << 3;
	info->xm = (arc->height * arc->height) << 3;
	info->yk = info->y * info->ym;
	if (!info->dy)
	    info->yk -= info->ym >> 1;
	if (!info->dx)
	{
	    info->xk = 0;
	    info->e = - (info->xm >> 3);
	}
	else
	{
	    info->y++;
	    info->yk += info->ym;
	    info->xk = -(info->xm >> 1);
	    info->e = info->xk - info->yk;
	}
    }
}

static void
miFillArcDSetup(xArc *arc, miFillArcDRec *info)
{
    /* h^2 * (2x - 2xorg)^2 = w^2 * h^2 - w^2 * (2y - 2yorg)^2 */
    /* even: xorg = yorg = 0   odd:  xorg = .5, yorg = -.5 */
    info->y = arc->height >> 1;
    info->dy = arc->height & 1;
    info->yorg = arc->y + info->y;
    info->dx = arc->width & 1;
    info->xorg = arc->x + (arc->width >> 1) + info->dx;
    info->dx = 1 - info->dx;
    info->ym = ((double)arc->width) * (arc->width * 8);
    info->xm = ((double)arc->height) * (arc->height * 8);
    info->yk = info->y * info->ym;
    if (!info->dy)
	info->yk -= info->ym / 2.0;
    if (!info->dx)
    {
	info->xk = 0;
	info->e = - (info->xm / 8.0);
    }
    else
    {
	info->y++;
	info->yk += info->ym;
	info->xk = -info->xm / 2.0;
	info->e = info->xk - info->yk;
    }
}

static void
miGetArcEdge(
	     xArc *arc,
	     miSliceEdgePtr edge,
	     int k,
	     Bool top, 
	     Bool left )
{
    int xady, y;

    y = arc->height >> 1;
    if (!(arc->width & 1))
	y++;
    if (!top)
    {
	y = -y;
	if (arc->height & 1)
	    y--;
    }
    xady = k + y * edge->dx;
    if (xady <= 0)
	edge->x = - ((-xady) / edge->dy + 1);
    else
	edge->x = (xady - 1) / edge->dy;
    edge->e = xady - edge->x * edge->dy;
    if ((top && (edge->dx < 0)) || (!top && (edge->dx > 0)))
	edge->e = edge->dy - edge->e + 1;
    if (left)
	edge->x++;
    edge->x += arc->x + (arc->width >> 1);
    if (edge->dx > 0)
    {
	edge->deltax = 1;
	edge->stepx = edge->dx / edge->dy;
	edge->dx = edge->dx % edge->dy;
    }
    else
    {
	edge->deltax = -1;
	edge->stepx = - ((-edge->dx) / edge->dy);
	edge->dx = (-edge->dx) % edge->dy;
    }
    if (!top)
    {
	edge->deltax = -edge->deltax;
	edge->stepx = -edge->stepx;
    }
}

static void
miEllipseAngleToSlope (int angle, int width, int height, int *dxp, int *dyp,
		       double *d_dxp, double *d_dyp)
{
    int	    dx, dy;
    double  d_dx, d_dy, scale;
    Bool    negative_dx, negative_dy;

    switch (angle) {
    case 0:
	*dxp = -1;
	*dyp = 0;
	if (d_dxp) {
	    *d_dxp = width / 2.0;
	    *d_dyp = 0;
	}
	break;
    case QUADRANT:
	*dxp = 0;
	*dyp = 1;
	if (d_dxp) {
	    *d_dxp = 0;
	    *d_dyp = - height / 2.0;
	}
	break;
    case HALFCIRCLE:
	*dxp = 1;
	*dyp = 0;
	if (d_dxp) {
	    *d_dxp = - width / 2.0;
	    *d_dyp = 0;
	}
	break;
    case QUADRANT3:
	*dxp = 0;
	*dyp = -1;
	if (d_dxp) {
	    *d_dxp = 0;
	    *d_dyp = height / 2.0;
	}
	break;
    default:
	d_dx = Dcos(angle) * width;
	d_dy = Dsin(angle) * height;
	if (d_dxp) {
	    *d_dxp = d_dx / 2.0;
	    *d_dyp = - d_dy / 2.0;
	}
	negative_dx = FALSE;
	if (d_dx < 0.0)
	{
	    d_dx = -d_dx;
	    negative_dx = TRUE;
	}
	negative_dy = FALSE;
	if (d_dy < 0.0)
	{
	    d_dy = -d_dy;
	    negative_dy = TRUE;
	}
	scale = d_dx;
	if (d_dy > d_dx)
	    scale = d_dy;
	dx = floor ((d_dx * 32768) / scale + 0.5);
	if (negative_dx)
	    dx = -dx;
	*dxp = dx;
	dy = floor ((d_dy * 32768) / scale + 0.5);
	if (negative_dy)
	    dy = -dy;
	*dyp = dy;
	break;
    }
}

static void
miGetPieEdge(
	     xArc *arc,
	     int angle,
	     miSliceEdgePtr edge,
	     Bool top, 
	     Bool left )
{
    int k;
    int	dx, dy;

    miEllipseAngleToSlope (angle, arc->width, arc->height, &dx, &dy, 0, 0);

    if (dy == 0)
    {
	edge->x = left ? -65536 : 65536;
	edge->stepx = 0;
	edge->e = 0;
	edge->dx = -1;
	return;
    }
    if (dx == 0)
    {
	edge->x = arc->x + (arc->width >> 1);
	if (left && (arc->width & 1))
	    edge->x++;
	else if (!left && !(arc->width & 1))
	    edge->x--;
	edge->stepx = 0;
	edge->e = 0;
	edge->dx = -1;
	return;
    }
    if (dy < 0) {
	dx = -dx;
	dy = -dy;
    }
    k = (arc->height & 1) ? dx : 0;
    if (arc->width & 1)
	k += dy;
    edge->dx = dx << 1;
    edge->dy = dy << 1;
    miGetArcEdge(arc, edge, k, top, left);
}

void
miFillArcSliceSetup(xArc *arc, miArcSliceRec *slice, GCPtr pGC)
{
    int angle1, angle2;

    angle1 = arc->angle1;
    if (arc->angle2 < 0)
    {
	angle2 = angle1;
	angle1 += arc->angle2;
    }
    else
	angle2 = angle1 + arc->angle2;
    while (angle1 < 0)
	angle1 += FULLCIRCLE;
    while (angle1 >= FULLCIRCLE)
	angle1 -= FULLCIRCLE;
    while (angle2 < 0)
	angle2 += FULLCIRCLE;
    while (angle2 >= FULLCIRCLE)
	angle2 -= FULLCIRCLE;
    slice->min_top_y = 0;
    slice->max_top_y = arc->height >> 1;
    slice->min_bot_y = 1 - (arc->height & 1);
    slice->max_bot_y = slice->max_top_y - 1;
    slice->flip_top = FALSE;
    slice->flip_bot = FALSE;
    if (pGC->arcMode == ArcPieSlice)
    {
	slice->edge1_top = (angle1 < HALFCIRCLE);
	slice->edge2_top = (angle2 <= HALFCIRCLE);
	if ((angle2 == 0) || (angle1 == HALFCIRCLE))
	{
	    if (angle2 ? slice->edge2_top : slice->edge1_top)
		slice->min_top_y = slice->min_bot_y;
	    else
		slice->min_top_y = arc->height;
	    slice->min_bot_y = 0;
	}
	else if ((angle1 == 0) || (angle2 == HALFCIRCLE))
	{
	    slice->min_top_y = slice->min_bot_y;
	    if (angle1 ? slice->edge1_top : slice->edge2_top)
		slice->min_bot_y = arc->height;
	    else
		slice->min_bot_y = 0;
	}
	else if (slice->edge1_top == slice->edge2_top)
	{
	    if (angle2 < angle1)
	    {
		slice->flip_top = slice->edge1_top;
		slice->flip_bot = !slice->edge1_top;
	    }
	    else if (slice->edge1_top)
	    {
		slice->min_top_y = 1;
		slice->min_bot_y = arc->height;
	    }
	    else
	    {
		slice->min_bot_y = 0;
		slice->min_top_y = arc->height;
	    }
	}
	miGetPieEdge(arc, angle1, &slice->edge1,
		     slice->edge1_top, !slice->edge1_top);
	miGetPieEdge(arc, angle2, &slice->edge2,
		     slice->edge2_top, slice->edge2_top);
    }
    else
    {
	double w2, h2, x1, y1, x2, y2, dx, dy, scale;
	int signdx, signdy, y, k;
	Bool isInt1 = TRUE, isInt2 = TRUE;

	w2 = (double)arc->width / 2.0;
	h2 = (double)arc->height / 2.0;
	if ((angle1 == 0) || (angle1 == HALFCIRCLE))
	{
	    x1 = angle1 ? -w2 : w2;
	    y1 = 0.0;
	}
	else if ((angle1 == QUADRANT) || (angle1 == QUADRANT3))
	{
	    x1 = 0.0;
	    y1 = (angle1 == QUADRANT) ? h2 : -h2;
	}
	else
	{
	    isInt1 = FALSE;
	    x1 = Dcos(angle1) * w2;
	    y1 = Dsin(angle1) * h2;
	}
	if ((angle2 == 0) || (angle2 == HALFCIRCLE))
	{
	    x2 = angle2 ? -w2 : w2;
	    y2 = 0.0;
	}
	else if ((angle2 == QUADRANT) || (angle2 == QUADRANT3))
	{
	    x2 = 0.0;
	    y2 = (angle2 == QUADRANT) ? h2 : -h2;
	}
	else
	{
	    isInt2 = FALSE;
	    x2 = Dcos(angle2) * w2;
	    y2 = Dsin(angle2) * h2;
	}
	dx = x2 - x1;
	dy = y2 - y1;
	if (arc->height & 1)
	{
	    y1 -= 0.5;
	    y2 -= 0.5;
	}
	if (arc->width & 1)
	{
	    x1 += 0.5;
	    x2 += 0.5;
	}
	if (dy < 0.0)
	{
	    dy = -dy;
	    signdy = -1;
	}
	else
	    signdy = 1;
	if (dx < 0.0)
	{
	    dx = -dx;
	    signdx = -1;
	}
	else
	    signdx = 1;
	if (isInt1 && isInt2)
	{
	    slice->edge1.dx = dx * 2;
	    slice->edge1.dy = dy * 2;
	}
	else
	{
	    scale = (dx > dy) ? dx : dy;
	    slice->edge1.dx = floor((dx * 32768) / scale + .5);
	    slice->edge1.dy = floor((dy * 32768) / scale + .5);
	}
	if (!slice->edge1.dy)
	{
	    if (signdx < 0)
	    {
		y = floor(y1 + 1.0);
		if (y >= 0)
		{
		    slice->min_top_y = y;
		    slice->min_bot_y = arc->height;
		}
		else
		{
		    slice->max_bot_y = -y - (arc->height & 1);
		}
	    }
	    else
	    {
		y = floor(y1);
		if (y >= 0)
		    slice->max_top_y = y;
		else
		{
		    slice->min_top_y = arc->height;
		    slice->min_bot_y = -y - (arc->height & 1);
		}
	    }
	    slice->edge1_top = TRUE;
	    slice->edge1.x = 65536;
	    slice->edge1.stepx = 0;
	    slice->edge1.e = 0;
	    slice->edge1.dx = -1;
	    slice->edge2 = slice->edge1;
	    slice->edge2_top = FALSE;
	}
	else if (!slice->edge1.dx)
	{
	    if (signdy < 0)
		x1 -= 1.0;
	    slice->edge1.x = ceil(x1);
	    slice->edge1_top = signdy < 0;
	    slice->edge1.x += arc->x + (arc->width >> 1);
	    slice->edge1.stepx = 0;
	    slice->edge1.e = 0;
	    slice->edge1.dx = -1;
	    slice->edge2_top = !slice->edge1_top;
	    slice->edge2 = slice->edge1;
	}
	else
	{
	    if (signdx < 0)
		slice->edge1.dx = -slice->edge1.dx;
	    if (signdy < 0)
		slice->edge1.dx = -slice->edge1.dx;
	    k = ceil(((x1 + x2) * slice->edge1.dy - (y1 + y2) * slice->edge1.dx) / 2.0);
	    slice->edge2.dx = slice->edge1.dx;
	    slice->edge2.dy = slice->edge1.dy;
	    slice->edge1_top = signdy < 0;
	    slice->edge2_top = !slice->edge1_top;
	    miGetArcEdge(arc, &slice->edge1, k,
			 slice->edge1_top, !slice->edge1_top);
	    miGetArcEdge(arc, &slice->edge2, k,
			 slice->edge2_top, slice->edge2_top);
	}
    }
}

#define ADDSPANS() \
    pts->x = xorg - x; \
    pts->y = yorg - y; \
    *wids = slw; \
    pts++; \
    wids++; \
    if (miFillArcLower(slw)) \
    { \
	pts->x = xorg - x; \
	pts->y = yorg + y + dy; \
	pts++; \
	*wids++ = slw; \
    }

static void
miFillEllipseI(
	       DrawablePtr pDraw,
	       GCPtr pGC,
	       xArc *arc )
{
    int x, y, e;
    int yk, xk, ym, xm, dx, dy, xorg, yorg;
    int slw;
    miFillArcRec info;
    DDXPointPtr points;
    DDXPointPtr pts;
    int *widths;
    int *wids;

    points = xalloc(sizeof(DDXPointRec) * arc->height);
    if (!points)
	return;
    widths = xalloc(sizeof(int) * arc->height);
    if (!widths)
    {
	xfree(points);
	return;
    }
    miFillArcSetup(arc, &info);
    MIFILLARCSETUP();
    if (pGC->miTranslate)
    {
	xorg += pDraw->x;
	yorg += pDraw->y;
    }
    pts = points;
    wids = widths;
    while (y > 0)
    {
	MIFILLARCSTEP(slw);
	ADDSPANS();
    }
    (*pGC->ops->FillSpans)(pDraw, pGC, pts - points, points, widths, FALSE);
    xfree(widths);
    xfree(points);
}

static void
miFillEllipseD(
	       DrawablePtr pDraw,
	       GCPtr pGC,
	       xArc *arc )
{
    int x, y;
    int xorg, yorg, dx, dy, slw;
    double e, yk, xk, ym, xm;
    miFillArcDRec info;
    DDXPointPtr points;
    DDXPointPtr pts;
    int *widths;
    int *wids;

    points = xalloc(sizeof(DDXPointRec) * arc->height);
    if (!points)
	return;
    widths = xalloc(sizeof(int) * arc->height);
    if (!widths)
    {
	xfree(points);
	return;
    }
    miFillArcDSetup(arc, &info);
    MIFILLARCSETUP();
    if (pGC->miTranslate)
    {
	xorg += pDraw->x;
	yorg += pDraw->y;
    }
    pts = points;
    wids = widths;
    while (y > 0)
    {
	MIFILLARCSTEP(slw);
	ADDSPANS();
    }
    (*pGC->ops->FillSpans)(pDraw, pGC, pts - points, points, widths, FALSE);
    xfree(widths);
    xfree(points);
}

#define ADDSPAN(l,r) \
    if (r >= l) \
    { \
	pts->x = l; \
	pts->y = ya; \
	pts++; \
	*wids++ = r - l + 1; \
    }

#define ADDSLICESPANS(flip) \
    if (!flip) \
    { \
	ADDSPAN(xl, xr); \
    } \
    else \
    { \
	xc = xorg - x; \
	ADDSPAN(xc, xr); \
	xc += slw - 1; \
	ADDSPAN(xl, xc); \
    }

static void
miFillArcSliceI(
		DrawablePtr pDraw,
		GCPtr pGC,
		xArc *arc )
{
    int yk, xk, ym, xm, dx, dy, xorg, yorg, slw;
    int x, y, e;
    miFillArcRec info;
    miArcSliceRec slice;
    int ya, xl, xr, xc;
    DDXPointPtr points;
    DDXPointPtr pts;
    int *widths;
    int *wids;

    miFillArcSetup(arc, &info);
    miFillArcSliceSetup(arc, &slice, pGC);
    MIFILLARCSETUP();
    slw = arc->height;
    if (slice.flip_top || slice.flip_bot)
	slw += (arc->height >> 1) + 1;
    points = xalloc(sizeof(DDXPointRec) * slw);
    if (!points)
	return;
    widths = xalloc(sizeof(int) * slw);
    if (!widths)
    {
	xfree(points);
	return;
    }
    if (pGC->miTranslate)
    {
	xorg += pDraw->x;
	yorg += pDraw->y;
	slice.edge1.x += pDraw->x;
	slice.edge2.x += pDraw->x;
    }
    pts = points;
    wids = widths;
    while (y > 0)
    {
	MIFILLARCSTEP(slw);
	MIARCSLICESTEP(slice.edge1);
	MIARCSLICESTEP(slice.edge2);
	if (miFillSliceUpper(slice))
	{
	    ya = yorg - y;
	    MIARCSLICEUPPER(xl, xr, slice, slw);
	    ADDSLICESPANS(slice.flip_top);
	}
	if (miFillSliceLower(slice))
	{
	    ya = yorg + y + dy;
	    MIARCSLICELOWER(xl, xr, slice, slw);
	    ADDSLICESPANS(slice.flip_bot);
	}
    }
    (*pGC->ops->FillSpans)(pDraw, pGC, pts - points, points, widths, FALSE);
    xfree(widths);
    xfree(points);
}

static void
miFillArcSliceD(
		DrawablePtr pDraw,
		GCPtr pGC,
		xArc *arc )
{
    int x, y;
    int dx, dy, xorg, yorg, slw;
    double e, yk, xk, ym, xm;
    miFillArcDRec info;
    miArcSliceRec slice;
    int ya, xl, xr, xc;
    DDXPointPtr points;
    DDXPointPtr pts;
    int *widths;
    int *wids;

    miFillArcDSetup(arc, &info);
    miFillArcSliceSetup(arc, &slice, pGC);
    MIFILLARCSETUP();
    slw = arc->height;
    if (slice.flip_top || slice.flip_bot)
	slw += (arc->height >> 1) + 1;
    points = xalloc(sizeof(DDXPointRec) * slw);
    if (!points)
	return;
    widths = xalloc(sizeof(int) * slw);
    if (!widths)
    {
	xfree(points);
	return;
    }
    if (pGC->miTranslate)
    {
	xorg += pDraw->x;
	yorg += pDraw->y;
	slice.edge1.x += pDraw->x;
	slice.edge2.x += pDraw->x;
    }
    pts = points;
    wids = widths;
    while (y > 0)
    {
	MIFILLARCSTEP(slw);
	MIARCSLICESTEP(slice.edge1);
	MIARCSLICESTEP(slice.edge2);
	if (miFillSliceUpper(slice))
	{
	    ya = yorg - y;
	    MIARCSLICEUPPER(xl, xr, slice, slw);
	    ADDSLICESPANS(slice.flip_top);
	}
	if (miFillSliceLower(slice))
	{
	    ya = yorg + y + dy;
	    MIARCSLICELOWER(xl, xr, slice, slw);
	    ADDSLICESPANS(slice.flip_bot);
	}
    }
    (*pGC->ops->FillSpans)(pDraw, pGC, pts - points, points, widths, FALSE);
    xfree(widths);
    xfree(points);
}

/* MIPOLYFILLARC -- The public entry for the PolyFillArc request.
 * Since we don't have to worry about overlapping segments, we can just
 * fill each arc as it comes.
 */
void
miPolyFillArc(DrawablePtr pDraw, GCPtr pGC, int narcs, xArc *parcs)
{
    int i;
    xArc *arc;

    for(i = narcs, arc = parcs; --i >= 0; arc++)
    {
	if (miFillArcEmpty(arc))
	    continue;
	if ((arc->angle2 >= FULLCIRCLE) || (arc->angle2 <= -FULLCIRCLE))
	{
	    if (miCanFillArc(arc))
		miFillEllipseI(pDraw, pGC, arc);
	    else
		miFillEllipseD(pDraw, pGC, arc);
	}
	else
	{
	    if (miCanFillArc(arc))
		miFillArcSliceI(pDraw, pGC, arc);
	    else
		miFillArcSliceD(pDraw, pGC, arc);
	}
    }
}